From 0be550f6ec873fbd55f3f38f9ed130d2a181e4a7 Mon Sep 17 00:00:00 2001
From: Jamie Portsmouth <jamie.portsmouth@autodesk.com>
Date: Sat, 24 Aug 2024 19:45:32 +0100
Subject: [PATCH 1/5] Add section describing the "recommended logic needed to
 determine which of the parameters can be disabled"

---
 parametrization.md.html | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/parametrization.md.html b/parametrization.md.html
index 7351597..83e76e4 100644
--- a/parametrization.md.html
+++ b/parametrization.md.html
@@ -72,6 +72,46 @@
 | `geometry_coat_normal`                | Coat Normal         | `vector3` | N/A               |               | unperturbed normal   |                  |
 | `geometry_coat_tangent`               | Coat Tangent        | `vector3` | N/A               |               | unperturbed tangent  |                  |
 
+
+## UI disabling logic
+
+The structure of the OpenPBR tree of layer and mix operations implies that some parameters have no effect if other parameters take certain values.
+Thus it can be helpful in the UI design for the shader to reflect this by disabling (e.g. greying out) those controls which are irrelevant in the current context.
+
+To facilitate this aspect of the UI design, we provide here in Python pseudocode form the recommended logic needed to determine which of the parameters can be disabled. This employs a function `disable(P, skip=[])` where the arguments `P` and the optional `skip` are a prefix string (or list of prefix strings). Then all parameters with names matching any of the prefixes in `P` should be disabled, except for those matching any in `skip`.
+
+```python
+   has_fuzz              = (fuzz_weight > 0.0)
+   has_coat              = (coat_weight > 0.0)
+
+   has_metal             = (base_metalness > 0.0)
+   has_dielectric        = (base_metalness < 1.0)
+   has_dielectric_transp = has_dielectric && (transmission_weight > 0.0)
+   has_dielectric_opaque = has_dielectric && (transmission_weight < 1.0)
+   has_subsurface        = has_dielectric_opaque && (subsurface_weight > 0.0)
+   has_diffuse           = has_dielectric_opaque && (subsurface_weight < 1.0)
+
+   if (!has_fuzz)                            disable("fuzz", skip="fuzz_weight")
+   if (!has_coat)                            disable("coat", skip="coat_weight")
+                                             disable("geometry_coat_tangent")
+   if (!has_dielectric)                      disable("specular_ior")
+   if (!has_dielectric_transp)               disable("transmission", skip="transmission_weight")
+   if (!has_dielectric_opaque && !has_metal) disable(["base_weight", "base_color"])
+   if (!has_subsurface)                      disable("subsurface", skip="subsurface_weight")
+   if (!has_diffuse)                         disable("base_diffuse_roughness")
+   if (specular_weight == 0)                 disable("specular", skip="specular_weight")
+                                             disable("geometry_tangent")
+   if (thin_film_weight == 0)                disable("thin_film", skip="thin_film_weight")
+
+   # In thin-walled mode, the volumetric medium is infinitesimally thin so the parameters controlling
+   # the MFP of the medium are irrelevant
+   if (geometry_thin_walled)
+      disable("transmission", skip=["transmission_weight", "transmission_color"])
+      disable("subsurface_radius") # (NB, also disables subsurface_radius_scale)
+```
+
+
+
 <!-- Markdeep: -->
 <style class="fallback">
    body { visibility:hidden }

From 5a736f8be04f295eb2dc2134ccb85ca7a5cbaeed Mon Sep 17 00:00:00 2001
From: Jamie Portsmouth <jamie.portsmouth@autodesk.com>
Date: Sat, 24 Aug 2024 19:52:36 +0100
Subject: [PATCH 2/5] tweak

---
 parametrization.md.html | 1 -
 1 file changed, 1 deletion(-)

diff --git a/parametrization.md.html b/parametrization.md.html
index 83e76e4..188170e 100644
--- a/parametrization.md.html
+++ b/parametrization.md.html
@@ -83,7 +83,6 @@
 ```python
    has_fuzz              = (fuzz_weight > 0.0)
    has_coat              = (coat_weight > 0.0)
-
    has_metal             = (base_metalness > 0.0)
    has_dielectric        = (base_metalness < 1.0)
    has_dielectric_transp = has_dielectric && (transmission_weight > 0.0)

From e6d3d28967fbb729996055389db2cfc5a21e2c9f Mon Sep 17 00:00:00 2001
From: Jamie Portsmouth <jamie.portsmouth@autodesk.com>
Date: Sat, 24 Aug 2024 20:53:06 +0100
Subject: [PATCH 3/5] Wording improvement

---
 parametrization.md.html | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/parametrization.md.html b/parametrization.md.html
index 188170e..1e90d5c 100644
--- a/parametrization.md.html
+++ b/parametrization.md.html
@@ -76,7 +76,7 @@
 ## UI disabling logic
 
 The structure of the OpenPBR tree of layer and mix operations implies that some parameters have no effect if other parameters take certain values.
-Thus it can be helpful in the UI design for the shader to reflect this by disabling (e.g. greying out) those controls which are irrelevant in the current context.
+It can be a helpful cue for artists if the UI design for the shader reflects this by disabling (e.g. greying out) those controls which are irrelevant in the current context.
 
 To facilitate this aspect of the UI design, we provide here in Python pseudocode form the recommended logic needed to determine which of the parameters can be disabled. This employs a function `disable(P, skip=[])` where the arguments `P` and the optional `skip` are a prefix string (or list of prefix strings). Then all parameters with names matching any of the prefixes in `P` should be disabled, except for those matching any in `skip`.
 

From 1c9c1a8580340b1b5a3b7b6c58ad05dee46e8228 Mon Sep 17 00:00:00 2001
From: Jamie Portsmouth <jamie.portsmouth@autodesk.com>
Date: Wed, 28 Aug 2024 19:46:44 +0100
Subject: [PATCH 4/5] Fix pseudocode for UI disabling logic to be actual Python

---
 parametrization.md.html | 53 +++++++++++++++++++++--------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/parametrization.md.html b/parametrization.md.html
index 1e90d5c..36c03e9 100644
--- a/parametrization.md.html
+++ b/parametrization.md.html
@@ -81,32 +81,30 @@
 To facilitate this aspect of the UI design, we provide here in Python pseudocode form the recommended logic needed to determine which of the parameters can be disabled. This employs a function `disable(P, skip=[])` where the arguments `P` and the optional `skip` are a prefix string (or list of prefix strings). Then all parameters with names matching any of the prefixes in `P` should be disabled, except for those matching any in `skip`.
 
 ```python
-   has_fuzz              = (fuzz_weight > 0.0)
-   has_coat              = (coat_weight > 0.0)
-   has_metal             = (base_metalness > 0.0)
-   has_dielectric        = (base_metalness < 1.0)
-   has_dielectric_transp = has_dielectric && (transmission_weight > 0.0)
-   has_dielectric_opaque = has_dielectric && (transmission_weight < 1.0)
-   has_subsurface        = has_dielectric_opaque && (subsurface_weight > 0.0)
-   has_diffuse           = has_dielectric_opaque && (subsurface_weight < 1.0)
-
-   if (!has_fuzz)                            disable("fuzz", skip="fuzz_weight")
-   if (!has_coat)                            disable("coat", skip="coat_weight")
-                                             disable("geometry_coat_tangent")
-   if (!has_dielectric)                      disable("specular_ior")
-   if (!has_dielectric_transp)               disable("transmission", skip="transmission_weight")
-   if (!has_dielectric_opaque && !has_metal) disable(["base_weight", "base_color"])
-   if (!has_subsurface)                      disable("subsurface", skip="subsurface_weight")
-   if (!has_diffuse)                         disable("base_diffuse_roughness")
-   if (specular_weight == 0)                 disable("specular", skip="specular_weight")
-                                             disable("geometry_tangent")
-   if (thin_film_weight == 0)                disable("thin_film", skip="thin_film_weight")
-
-   # In thin-walled mode, the volumetric medium is infinitesimally thin so the parameters controlling
-   # the MFP of the medium are irrelevant
-   if (geometry_thin_walled)
-      disable("transmission", skip=["transmission_weight", "transmission_color"])
-      disable("subsurface_radius") # (NB, also disables subsurface_radius_scale)
+has_fuzz              = (fuzz_weight > 0.0)
+has_coat              = (coat_weight > 0.0)
+has_metal             = (base_metalness > 0.0)
+has_dielectric        = (base_metalness < 1.0)
+has_dielectric_transp = has_dielectric and (transmission_weight > 0.0)
+has_dielectric_opaque = has_dielectric and (transmission_weight < 1.0)
+has_subsurface        = has_dielectric_opaque and (subsurface_weight > 0.0)
+has_diffuse           = has_dielectric_opaque and (subsurface_weight < 1.0)
+if not has_fuzz:                                disable("fuzz", skip="fuzz_weight")
+if not has_coat:
+                                                disable("coat", skip="coat_weight")
+                                                disable("geometry_coat_tangent")
+if not has_dielectric:                          disable("specular_ior")
+if not has_dielectric_transp:                   disable("transmission", skip="transmission_weight")
+if not has_dielectric_opaque and not has_metal: disable(["base_weight", "base_color"])
+if not has_subsurface:                          disable("subsurface", skip="subsurface_weight")
+if not has_diffuse:                             disable("base_diffuse_roughness")
+if (specular_weight == 0):                      disable("specular", skip="specular_weight")
+if (thin_film_weight == 0):                     disable("thin_film", skip="thin_film_weight")
+# In thin-walled mode, the volumetric medium is infinitesimally thin so the parameters controlling
+# the MFP of the medium are irrelevant
+if (geometry_thin_walled):
+   disable("transmission", skip=["transmission_weight", "transmission_color"])
+   disable("subsurface_radius") # (NB, also disables subsurface_radius_scale)
 ```
 
 
@@ -123,3 +121,6 @@
 <script>
 window.alreadyProcessedMarkdeep || (document.body.style.visibility="visible")
 </script>
+
+
+

From 3564c96c0fedcd4c1d20186cf320683e8235586b Mon Sep 17 00:00:00 2001
From: Jamie Portsmouth <jamie.portsmouth@autodesk.com>
Date: Fri, 11 Oct 2024 17:31:03 +0100
Subject: [PATCH 5/5] Fix bug in base_weight/base_color disabling logic

---
 parametrization.md.html | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/parametrization.md.html b/parametrization.md.html
index 36c03e9..fef8789 100644
--- a/parametrization.md.html
+++ b/parametrization.md.html
@@ -95,7 +95,7 @@
                                                 disable("geometry_coat_tangent")
 if not has_dielectric:                          disable("specular_ior")
 if not has_dielectric_transp:                   disable("transmission", skip="transmission_weight")
-if not has_dielectric_opaque and not has_metal: disable(["base_weight", "base_color"])
+if (not has_diffuse and not has_metal):         disable(["base_weight", "base_color"])
 if not has_subsurface:                          disable("subsurface", skip="subsurface_weight")
 if not has_diffuse:                             disable("base_diffuse_roughness")
 if (specular_weight == 0):                      disable("specular", skip="specular_weight")